**3. Fibroblast cell cultures**

The development of a non-invasive sampling method for obtaining viable tissue samples for cell cultures from skin biopsies of free-ranging and stranded cetaceans was described by Marsili *et al.* [14]. Successful cell cultures were obtained from all the animals. After the biopsy, skin samples were stored in sterile medium MEM Eagle Earle's salts w/L-glutamine and sodium bicarbonate (Mascia Brunelli, Milan, Italy) + 10% gamma irradiated fetal calf serum (Mascia Brunelli) + 1% MEM not essential aminoacids (NEAA) solution 100x (Mascia Brunelli) + 1% Penicillin/Streptomycin 100x (Mascia Brunelli) + 0.1% Amphotericin B 100x (Mascia Brunelli) at room temperature and was processed within 24 h of collection. In the laboratory, each sample was washed with Earle's balanced salt solution (EBSS; Mascia Brunelli) containing antibiotic (Penicillin/Streptomycin 100x [Mascia Brunelli]) and antimycotic (Amphotericin B 100x [Mascia Brunelli]) solutions. All specimens were handled using sterile techniques. Initially, the collected tissue was cut into small pieces with curved surgical scissors, placed in 30-mm Petri dishes and incubated with Trypsin-EDTA solution 1x (Mascia Brunelli) for 15 min at 37°C. The biopsy fragments were washed again and then placed in Falcon 25 flasks, moistened with medium. After 24 h at 37°C in an incubator with 5% CO2, the cultures were covered with 1 ml of medium. Half of the culture medium was replaced every 48 h with fresh medium.
